Parallel Switch Diode Circuit Reduces Current Inaccuracy
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Solution Overview
Problem
Existing diode circuits face accuracy issues due to offset voltages in operational amplifiers, leading to unwanted current flow and oscillations, which affect electromagnetic compatibility and application reliability.
Innovation Solution
A circuit with multiple parallel switches and a control circuit that compares voltage to a reference voltage, selectively turning on and off switches to maintain voltage close to the reference, reducing current inaccuracy and peak currents through sequential switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single switch controlled by a comparator is used to implement diode function, then the circuit structure is simple, but offset voltage causes current inaccuracy and unwanted oscillations
Solution Approach 1:
The single switch is divided into multiple parallel switches (at least two), each controlled by its own control circuit. This segmentation allows the system to distribute the switching action across multiple devices, reducing the impact of offset voltage on any single switch and thereby improving current accuracy while maintaining reasonable structural complexity.
Solution Approach 2:
A reference voltage is introduced as an intermediary element in the control mechanism. By comparing the voltage across the terminals against this reference voltage rather than directly controlling a single switch, the system achieves more precise control over the switching threshold, reducing unwanted oscillations and improving current accuracy.
2Measurement precision
If offset voltage is reduced by selecting higher precision operational amplifiers, then current accuracy improves, but device cost and complexity increase
Solution Approach 1:
Instead of relying on a single high-precision operational amplifier, the system segments the switching function across multiple switches with simpler control circuits. This approach achieves comparable or superior current accuracy without requiring expensive high-precision operational amplifiers, thereby reducing device complexity and cost.
Solution Approach 2:
The control circuits incorporate feedback mechanisms that monitor the voltage across the terminals and adjust the switching state accordingly. This feedback approach compensates for offset voltage effects dynamically, achieving high current accuracy without requiring high-precision operational amplifiers.
3Productivity
If a single switch turns on abruptly when voltage exceeds threshold, then the diode function is achieved, but peak currents cause electromagnetic compatibility issues
Solution Approach 1:
The abrupt switching action of a single switch is segmented across multiple parallel switches. When voltage exceeds the threshold, the control circuits distribute the switching action among the parallel switches, preventing any single switch from conducting a large peak current. This maintains fast switching response while reducing electromagnetic compatibility issues.
Solution Approach 2:
The control circuits dynamically adjust the switching state of each parallel switch based on the instantaneous voltage across the terminals. This dynamic control allows the system to respond quickly to voltage changes while distributing the current flow to avoid harmful peak currents, resolving the contradiction between switching speed and electromagnetic compatibility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly reduces current inaccuracy and peak currents, enhancing electromagnetic compatibility and application reliability by maintaining voltage close to the reference voltage and minimizing temperature-dependent current thresholds.
Implementation Method 1
comparing the voltage between the first and second terminals with a reference voltage
Data Source
AI summary
A circuit including: a plurality of first switches connected in parallel between a first terminal and a second terminal; and a control circuit capable of implementing the following steps at each period of a clock signal: comparing the voltage between the first and second terminals with a reference voltage; if the voltage between the first and second terminals is greater than the reference voltage, turning on one of the first switches without modifying the state of the other switches; and if the voltage between the first and second terminals is smaller than the reference voltage, turning off one of the first switches without modifying the state of the other switches.